Automatic transmission



Dec. 21,1937. c. P. HOPSON AUTOMATIC TRANSMISSION Filed March 2, 1936 3 Sheets-Sheet l lN VE N TOE CL/FFo/ao P HOP$0N A TTOENEYS 5 Sheets-Sheet 2 Dec. 21, 1937. c. P. HOPSON AUTOMATIC TRANSMISSION Filed March 2, 1 936 N M R w .m M M M m W M mB 0 Q 2 0 7 J mm 7 /5 NR 0. M W a mm NJ mu Q m -1 a 2 v m z m t @W m k Dec. 21, 1937. c. P. HOPSON AUTOMATIC TRANSMISSION File'd March 2, 1936 5 Sheets-Sheet 3 Q S Q Q Q ATTOEN E Y5 Patented DecQ'Z I 1937 15 V V NlTE D STATES, PATENT oFmcE AUTOMATIC TRANSMISSION fClifford Hopson, Bakersfield, Galif. Application March :2, 1936, Serial No. 66,644

8 Claims. (o 1 -3 37) -V This invention reiatesigenerallyzto.povver trans .7 elevation-antipathy iinisection,:oftheactuating; feriring mechanism.and'imoreparticularly.tonv-arimeans zfor'the overrunningrolutohyshowndnEigable speedxtransmissions. V ure-l; I I

An objectofthisiinvention isitocprovideavarie FigurevQ is -;a :transverse sectional view taken v 8 able speedztransmission which :is .:-automatic -.in on 1the-line ;9-29"Of :Ei-gure 3.

its operation to vary the .speedratio ;:between V 2 Referring specifically-.tothe:-drawings,- the Win driving and drivenrelementslincaccordanceqwith vention in its present gembodiment comprises the load. or, drag imposed onith'eld riven element, drivin nd drivenfelements inzthe formxofeooax and in such manner as to-obtainimaximum-effi ially rr ne h ft ll'land M i i wfi I 10 ciency and economy irom ai rimemcveriand/or tively in bearings |=2:'|-2 and.l 3 ---l:3v--in.-a suitable 10:

vehicle, or otherapparatuswith vwhich the transhousing 11 3a.

mission is operativelyvassociated. v 'ISplined on the shaft Ill betweenithe bearings .Another object of thisiinvention is to-provide l-z- -l-zisea worm ,114iwhich abutsjthrust bearin an automatic transmission of "the above dei -J nd infi m lylurged ly-on.theshalf 5 scribed character embodying meansiby whichithe t0 the em m sition shownrin Figur-esrl and]; effect of thefload or jdragj in varyingithe speed by m-heavyooH sp ng lvfirsurrlounding the, shaft ratio vbetween the "driving and driven elements L0andlabuttingthliust hearings-"H 1- e can be manually controlled-in such manner as v The W m con i ii a worm to renderthe mechanismresponsive'toagreater Wheel t8 fixed to a-transverseijack shaftJBJourload than "normally required toobtain a given a ed in bearings lit-20. ,Fixed totone enclof 116 20 speed ratio in order to compensate for various ha t L9 s a-hevel gcarzfll-constan ly meshingoperating conditions crrthe desiresof the-operaithaipinion gearizz fixedHto a1c0untershaft Z tor. h disposed in parallelism with the shafts Jflqand Aiurther objectof the inventionis-to provide l' journaledin a n ufi vand F d 25 an automatic transmission which canbem-anutovtheccountershaft between theibearing liand 25 ally adjusted or Set to selectively;provide-various 6 isra sleeve ,2!,havingrfixedthertooniarme predetermined speed ratios irrespective of the integral therewith gears 29 a d 3!]- V v amountof load ordr-ag imposed -;on thedriven .Thengears 28,-Z9 .and 30-respectively-meshconi m, stantly with gears .;3'i.,.32andl, 3.'3 ;to form three- 30 With these and otherobjects JIIQVJZBW theiintrains correspondin IfiSD y i0 tithe 0 30 vention consists in the combinationswand variatepand fhigh=gealts oifuan autom rangements of elements asset forth in .theyfolbiletransmis'sjionras interposed between the enlowing specificationsand particularly pointed-out gineand pro elling w eelsofvthe vehicl inthe appended claims. 7 a ;'I' he..gears,3i,.32 en lest.areffixedirespectively In the accompanying drawingsto the mdrivin lmem s 34,a 5nandi35aoof over- 35 Figure 1 is a viewshowing inplan (section one u inglbhltchesififi, 3? and ld mounted on, the form of automatic transmission'embodying lthis driven Shaft H l ween J rbearings 13- 51 invention; v V Theclutch 3'6 lisflof the .conventionaltlioll and Fi ure 2 is a view of the :automaticftransmis- Wedge fypesmvmin F g 9. andthenfllutoh 4o sion inside elevation and with-thewhousin gtherea d 31a are -of 'thejidehtical and (novel obnv40 structionshown' in Fi ures .4, 1.5 audio.

of in section; V I v Figure 3v is an enlarged.longitudinalesectional vThe d ving membersf34,r35.and;35S0ftth l1 -I view illustrating overrunningelutch mechanisms Spective'v clutches ,are journaled v.17 Jf i lw1 01199 and operating means therefor, embodied [inthe onithe f l I, whereasc'lthefidriven member'sjsa, 5 transmission; I

Figure 4 is an enlarged-iransverse sectional eyed to the shaft in orderjthat lnowerrfromt the viewvof-oneof the ,overrunning clutches-indish f "I an Joe transmitted to thfl'shaftl l'l enga-ged-positionland taken on thelineA-dof through y One O'fjthe olutchesfin'the manner Figure 3; to, be, later described.

. 5 Figures 5 and-6 are, fragmentary :views similar The clutches 31 andjla aresadaptediforcauto i 5 to Figure ibutshowing other 'positions. occupied m t c Operation in ,aw0rd rn e.withtthefloaid or by the clutches; 'drag imposed on the drive .jshait l0. jrhese Figure J7 is-an. .en1arged' transverse sectional clutches. and the mode .Qf QpeI1a t.iI 1 -.'them"willl view taken on the line 1--'l of FigureB; nowhedescribed, sand-Ma's the ,olutches arewide'n- 55 \liigure-Bisl-atfragmentary view partly"in-side ticalln,oonstrnotion sa ;desori l ion goi Hone N11155 39 and "39a respectively of theseclutChes-j-are suffice for both. However, in order to distinguish like parts of the clutches fromeach other, the numerals designating the parts of one clutch are provided with exponents.

The clutches each comprise a plurality of dogs or pawls 49, of which three are shown in Figure 4, equally spaced circumferentially on the driven member 39 of the clutch. These dogs each tiltably seat in a recess 4| formed in a connector 42 havinga rounded lug 43 at one end, seated freely in an opening 44 in the hub 45 of the driven member, and bearing upon the periphery of the driven shaft At its other end each of the connectors 42 is provided with an extension being a similar lobe 5|] for each connector, with the lobes being separated by concentrically recessed portions 52 on which the extensions of the connectors are adapted to ride in the disengaged position of the dogs shown in Figure 4.

Adjacent each dog and pivoted at 53 on the,

driven member 39 is an arm 54 on which is pivotally mounted at 55 a bell crank lever 56, one leg 51 of which extends through registering openings 58 and 59 in the hub 45 and in the shaft H for engagement with the periphery of the cam shaft 5| under the urging action of a spring 60 seating in sockets formed in the leg 51 and in a lug 6| on the driven member. This spring also functions to urge the lever 54 into engagement with a stop lug 62 projecting from the hub 45.

In the disengaged position of the dogs 49 wherein the leg 51 of each lever 56 rides upon one of the lobes 59, the other leg 63 of the lever engages the respective dog to retain the latter in a position in which its active peripheral surface 64 is disposed concentric with respect to the internal surface 65 of the driving member 35 against the urging action of a spring 66 seating in sockets in the dog and in a lug 61 projecting from the driven member 39. A cover plate 68 is secured to the driven member 39 to enclose the clutch mechanism.

In the operation of the clutch 31, and assuming that it is disengaged as shown in Figure 4, initial rotational movement of the cam shaft 5| from this position in the counter clockwise direction indicated by the arrow will cause the lobes 50 to rock the respective connectors 42 outwardly from the recesses 52 so that the extensions46 of the connectors rest upon the lobes as shown in Figure 5. This operation shifts the dogs 40 radially outward, but as the legs 63 of the respective bell crank levers 56 are engaging the dogs and are retaining the latter against tilting under the action of the respective springs 66, the driven member 39'will not be operatively connected to the driving member 35.

However, as this rotational movement of the cam shaft 5| is continued to the position shown in Figure 6, the lobes 59 will clear the legs 51' of the'respective levers 5B, permitting the latter under the action of the respective springs'BD to disengage the dogs 40. The springs 66 are now free to tilt the dogs, and as the connectors are still being maintained in their previous position by the lobs 50, the dogs will be rocked into binding engagement of their peripheral surfaces 64 with the internal surface 55 of the driving member 35. Thus with the driving member rotating in the clockwise direction shown by the arrow in Figures 4, 5 and 6, the tendency will be to maintain the dogs in binding engagement with the driving member. Hence the driven member 39 will be driven by the driving member so that the clutch operates as a single unit to correspondingly drive the shaft II.

In the reverse operation of the clutch to restore the same to its disengaged position, the reverse rotational movement of the cam shaft 5| from the position shown in Figure 6 will cause the lobes 59 of the cam shaft to reversely rock the respective levers 56 until their legs 63 engage the respective dogs. 40. However as the dogs are wedged so tight that they will not shift under the pressure of the levers 56, the springs 60 will yield, thereby permitting the levers 56 and the respective arms 54 to rock as a unit about the respective pivots 53.

Continued reverse rotational movement of the cam shaft to the position shown in Figure 4, during which the connectors 42 ride from the lobes 59 into the recesses 52, will permit the dogs to return to their non-tilted position clear of the driving member 35, thus disengaging the driven member therefrom; It is to be noted that the relative circumferential disposition of the lobes and recesses in the cam shaft, for the two clutches 31 and 31a, is such that the clutches will be engaged and disengaged successively, one clutch being maintained engaged while the other is being engaged, or vice versa.

In order to rock the cam shaft 5| and effect operation of the clutches as aforesaid, that end of the shaft confronting the shaft l0 and journaled in one of the bearings 3 is enlarged in diameter to form a cylindrical sleeve 69 which freely receives the enlarged cylindrical end portion or head 10 of the cam shaft 5| so as to provide an annular space ll between the sleeve and head. The sleeve is provided internally with a plurality of spirally arranged grooves 12, and the head is provided with an equal number of grooves 13 reversely spiralled to the grooves H as clearly shown in Figure 8. In the present instance the grooves are each three in number equally spaced circ'umferentially and are related so that when the cam shaft 5| occupies its position of rotational adjustment relative to the driven shaft II, as shown in Figure 6, and wherein the clutches 31 and 31a are engaged, the outer ends of the grooves 12 will directly confront the corresponding ends of the grooves 13.

Working in each of the grooves 12 and 13 are rollers 14 and 15, respectively, journaled, on a pin '15 mounted radially in a cup TI formed on one end of a stub shaft 18 journaled in a bearing 19 in one end of a yoke 8|), the opposite end of which freely receives the drive shaft l0 and is confined between the thrust bearings I5 and I! so that in response to axial feeding of the Worm 4 on the drive shaft against the action of the spring l6, from the extreme position shown in Figures 1 and 2, the yoke will be correspondingly moved to advance the cup 11 into the annular space H. As the cup 11 is thus advanced, the pairs of rollers 14 and I5 coact with the respective pairs of relatively reversely spiralled grooves 12 and I3 in rotating the cam shaft 5| in a clockwise direction as viewed in Figure 6 to first disengage the high gear clutch 31a. and then the intermediate gear clutch 31 during which movement of the cam shaft the cup 11 will'have been fully advanced into the annular space H.

The general operation of the automatic transmission is asfollows:

Let it be assumed that the transmission is in- 7 1;

' gear -clutch=31a.

aim-,etr

* an order to vary the loading upon the shaft H stalled in an automobile and that; the engine'there of is iii-operation, with the usual clutch of the automobile disengaged. this clutch is engaged to apply the power of the engine to the drive shaft H); the rotation of theworm 44 by the shaft is-opposed by the load or drag imposed on thedriven-shaft H by the resistance-of the auto-,

mobile to movementover'the road. It is-to be understood that in the normal positionof the transmission shown in Figures land 2, the overrunning clutches 36, BlandS-la; are engaged, as corresponds to ahigh gear condition tation through the high gear train 30, :33 in the As a'result;

direction of :the arrow in Figure 1. the worm wheel temporarily functions as a nut causing the worm to be fed axially'on the drive shaft by screwing its way relative to the teethof the *worm wheel. 'As thesprin'g I6 is beingcompressed in response to such axial feeding of the worm on the .drive'shaft, the yoke 88 is correspondingly moved to first disengage thehigh Should the resistance of the vehicle to forward motion stillbe in 'excess of the load imposed on the spring It by the axial feeding of the'worm, the worm continues to screw its way relative to the worm wheel, thus'further compressing'the spring l6 and advancing the'yoke 88 until the second gear clutch 31 is disengaged.

Assuming that with the high and intermediate gear trains unlocked by the disengagement of the respective clutches 31a and 31, that the resistance of the vehicle to forward motion is now less than the loading of the spring IS, the worm wheel 7 I48 commences to rotate and drive the shaft. ll through the low gear train 28, 3| and theoverrunning clutch 36. V

As'the vehicle starts-to move, the power ap plied to the driveshaft l 0, plus the potential energy ofthe spring l6, so'onexceeds the resistance of the'vehicle to forward'motion, thus permitting thesprin'g'IB toexertits'force 'in reversely shiftwith the low, intermediate and high gears reing the wormaxially on thedrive shaftsuntil the yoke 80 has been retracted sufficiently for the second gear clutch "31 'tobe re-engaged so that the vehicle is now being driven through the second gear train 29, 32 and the clutch 31.

Asthe speed of the vehicle increases with a corresponding decrease in the load imposed on the drive shaft I I, the spring vl6 in an effort to equalize its loading with that of the shaft continues to expand and further, 'reversely shift the worm axially until the yoke 80 has been retracted sufficiently for re-engagement 'of the high gear clutch 31a to'be effected, whereby the vehicle will be driven through the high gear train 30, 33 and the clutch 31a. a

It will be manifest that although the countershaft gears 28, 29 and are constantly in mesh spectively of the driving members 34, 35 and 35a 'of the respective clutches, the shaft [I with all at which the-mechanism will remain in any particular gear, a manuallynperable lever 81 suitably.

pivoted at =82 and engageable by meansof awoke 83 withone of the thrust bearings H can beactuated toinitially compress the spring l 6 tea greater load-than the normal load of the spring in the high gear position of the mechanism, to thus compensate for various operatingconditions and variations in "the gross weight of the vehicle,

Furthermore, the automatically operated yoke 88 can she-shifted manually by a handle lever 84, and set insecond or low gear positionin orderto obtain operation of the mechanism in either of these gears independent-of the automatic functioning of the mechanism. The mechanism can be latched in any gear position .by the provision of a manually releasable spring urged latch 85 mounted on'the lever 84.

Although there has been only one form of automatic transmission described, it is to be understood that various changesand modifications :may be-made therein without departing from thespirit of the invention and the spiritand scope of the appended claims.

"I claim: 7

1. An automatic transmission comprising a driving element; a driven element; and power transferring mechanism operatively connecting said-elements to vary the speed ratio between the elements in accordance'with the variations in loadon the driven element relative to powerapplied to the driving element; said mechanism :including a'plurality of differently .ratioed driving connections; a plurality of constantly meshing gearsone of which is mounted onzthe driving element' for rotation thereby to drive the otherlof said gears andlfor axial .feedingfrom one extreme position toanother on the driving element while or without driving said other of the.gears;. means for yieldinglyresisting the axial feeding ofsaid one of theigears; and means responsive to axial feeding of said one of the gears to render active a-rpredete'rmined oneof said driving connections.

2. An automatic transmission comprising a driving element; a driven element; and power transferring mechanism operatively connecting said .elementsto varythe speed ratio between the elements .in accordance with the variations in loadlon-the driven element relative to power applied -;to.;the driving element; said mechanism including a worm wheel; a worm constantly meshing with the worm wheel and slidably keyed on the driving element so as to rotate the worm wheel and yet be capable of axial feeding from one extreme position to another on the driving element while or without driving the worm wheel; a spring for resisting axial feeding of the worm;

and. clutches selectively responsive to axial feeding of the worm to render active a predetermined one of said driving connections.

3. An automatic transmission comprising a driving element; a driven element; a plurality of constantly meshing gears; means for mounting one of said gears on the driving element for rotation thereby to drive another of said gears, and for axial feeding on the driving element without driving the last mentioned gear; power transferring mechanism for operatively connecting the last mentioned gear to the driven element and including a plurality of differently ratioed gear trains by which the driven element can be driven from said last mentioned gear at different speeds relative to the speed of the driving element; means for yieldingly resisting axial feeding of said one of the gears in accordance with variations in load on the driven element relative tov power applied to the driving element; and means responsive to: axial feeding of said one of the gears to render active that one of the gear trains necessary to obtain a predetermined speed ratio between said elements in accordance with the load and power relationships thereof.

4. An automatic transmission comprising a driving shaft; a driven shaft; a worm wheel; a worm meshing with said wheel and splined on the drive shaft so as'to be capable of rotating the worm wheel yet be feedable axiallyby screwing its way relative to the worm Wheel without rotating the latter; power transferring mechanism for operatively connecting the worm wheel to the driven shaft and including a plurality of differently ratioed gear trains and overrunning clutches one for each train, by which the driven shaft can be driven from the worm wheel at different speeds relative to the speed of the driving element; a spring for yieldingly resisting axial feeding of the worm in accordance with variations in load on the driven shaft relative to power applied to the driving shaft, by enabling the worm to be advanced or retracted to a greater or less extent according as the load is increased or decreased; and means responsive to axial feeding of the worm for rendering active that one of the overrunning clutches necessary to obtain a predetermined speed ratio between said elements in accordance with the load and power relationships thereof.

5. An automatic transmission as embodied in claim 4, wherein said last means comprises a cam shaft for successively actuating said clutches as the cam shaft is rocked from one position to another; a reciprocably mounted member operated in response to axial feeding of the worm; and an operative connection between the cam shaft and said member by which reciprocating motion of the latter is translated into rotary motion to rock the cam shaft.

6. An automatic transmission as embodied in,

claim 4 wherein said last means comprises a cam shaft journaled for rocking movement in the driven shaft to successively actuate said clutches; a reciprocably mounted member operated in response to axial feeding of the worm; the driven shaft and cam shaft having correlated reversely spiralled grooves; and rollers carried by said mem- 7 her and working in said grooves for coaction.

therewith in rocking the cam shaft relative to the driven shaft upon reciprocation of said member.

'7. An automatic transmission comprising a driving element; a driven element; transmission mechanism operatively connecting said elements to drive the driven element at any one of a plurality of preselected different speeds relative to the driving element; said transmission mechanism including a plurality of gears one of which is mounted on the driving element to drive another of said gears, yet is shiftable axially of the driving element and relatively to said another of the gears without driving the latter; means for normally urging said one of the gears axially to a retracted position, and operating in accordance with variations in load on the driven element relative to power applied to the driving element, to cause said one of the gears to be advanced or retracted to a greater or less extent according as the load is increased or decreased; and means coacting with the transmission mechanism and said one of the gears,-by which axial feeding of the latter will cause the transmission mechanism to increase or decrease the'speed ratio between the driving and driven elements according as said one of the gears is advanced or retracted.

8. An automatic transmission comprising a driving element; a driven element; transmission mechanism operatively connecting said elements to drive the driven element at any one of a plurality of preselected different speeds relative to the driving element; said mechanism including .a worm and a worm wheel, the former of which is splined on the driving element to rotate the worm wheel, yet is rendered axially feedable by screwing its way relative to the teeth of the worm wheel without driving the latter; a spring normally urging the worm axially to a retracted position, and operating in accordance with variation in load on the driven element relative to power applied to the driving element to cause the worm to be advanced or retracted to a greater or less extent according as the load is increased or decreased; and means responsive to axial feeding of the worm to cause said mechanism to increase or decrease the speed ratio between said elements according as the worm is advanced or retracted.

CLIFFORD P. HOPSON. 

